Top 5 ways to mess with Earth's life
An article in Discovery News has featured the top 5 ways by which Earth's life can be affected adversely.india Updated: Mar 07, 2010 16:05 IST
An article in Discovery News has featured the top 5 ways by which Earth''s day can get messed up.
The first way for a day to get messed up is through earthquakes, as can be seen by the magnitude 8.8 earthquake in Chile on February 27, which shortened Earth''s day by about 1.26 microseconds.
The 2004 Sumatra-Andaman earthquake spawned a horrific tsunami throughout the Indian Ocean. It also shortened the day by about 2.7 microseconds.
Not all large quakes shorten the day, but both the Chile and Indonesian temblors were "megathrusts"; faults where the ocean floor is diving down underneath a piece of lighter continental crust on a grand scale.
Usually, the two tectonic plates are locked, storing up strain and seismic energy. When they pop, the ocean floor suddenly dives into the mantle, sometimes close to 100 feet in a few seconds.
Another way by which Earth''s day is affected is through global warming, as it makes our day longer.
Warm El Nino conditions that occur every few years in the tropical Pacific Ocean can lengthen the day up to a millisecond (1/1000th of a second) before subsiding again.
According to recent research, more warmth in the tropics could mean many more El Nino events.
With more energy getting pumped into the atmosphere, high-level winds will speed up. To conserve momentum in the Earth-atmosphere system, the planet will be forced to slow down.
The cumulative effect could be a half millisecond added to our day by the year 2100.
Glaciers can also affect earth''s day, as their absence since the last ice age is speeding up the planet about 0.6 milliseconds per day per century.
Surprisingly, trees can influence the rate at which the Earth spins, and that makes them mess up Earth''s day as well.
Every spring in the northern hemisphere, deciduous trees take nutrients out of the soil, carbon dioxide from the air, and build leaves.
Those leaves spin round and round high on tree limbs through the warm months, and then die off in the fall, dropping a huge amount of biomass down to the ground.
That mass imperceptibly speeds up Earth''s rotation, by about .0432 billionths of a second, somewhere around the limits of detection of today''s atomic clocks.
The fifth way by which Earth''s day is affected is by tides.
The Moon''s gravitational tug on our oceans causes the water to act like a brake on the solid earth, slowing rotation down by an average of 1.7 milliseconds per day per century.
First Published: Mar 04, 2010 19:59 IST